From 0e0ff29271df58e3bc545e40f5432c436e8bd76b Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Thu, 12 Nov 2009 04:37:50 +0000
Subject: [PATCH] switch jump threading to use getPredicateOnEdge in one place
 making the new LVI stuff smart enough to subsume some special cases in the
 old code.  Disable them when LVI is around, the testcase still passes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86951 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Scalar/JumpThreading.cpp | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/lib/Transforms/Scalar/JumpThreading.cpp b/lib/Transforms/Scalar/JumpThreading.cpp
index 47bebf90d3c..e7a87e098d0 100644
--- a/lib/Transforms/Scalar/JumpThreading.cpp
+++ b/lib/Transforms/Scalar/JumpThreading.cpp
@@ -377,6 +377,7 @@ ComputeValueKnownInPredecessors(Value *V, BasicBlock *BB,PredValueInfo &Result){
     // If comparing a live-in value against a constant, see if we know the
     // live-in value on any predecessors.
     if (LVI && isa<Constant>(Cmp->getOperand(1)) &&
+        Cmp->getType()->isInteger() && // Not vector compare.
         (!isa<Instruction>(Cmp->getOperand(0)) ||
          cast<Instruction>(Cmp->getOperand(0))->getParent() != BB)) {
       Constant *RHSCst = cast<Constant>(Cmp->getOperand(1));
@@ -384,14 +385,14 @@ ComputeValueKnownInPredecessors(Value *V, BasicBlock *BB,PredValueInfo &Result){
       for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
         // If the value is known by LazyValueInfo to be a constant in a
         // predecessor, use that information to try to thread this block.
-        Constant *PredCst = LVI->getConstantOnEdge(Cmp->getOperand(0), *PI, BB);
-        if (PredCst == 0)
+        LazyValueInfo::Tristate
+          Res = LVI->getPredicateOnEdge(Cmp->getPredicate(), Cmp->getOperand(0),
+                                        RHSCst, *PI, BB);
+        if (Res == LazyValueInfo::Unknown)
           continue;
-        
-        // Constant fold the compare.
-        Value *Res = SimplifyCmpInst(Cmp->getPredicate(), PredCst, RHSCst, TD);
-        if (isa<ConstantInt>(Res) || isa<UndefValue>(Res))
-          Result.push_back(std::make_pair(dyn_cast<ConstantInt>(Res), *PI));
+
+        Constant *ResC = ConstantInt::get(Cmp->getType(), Res);
+        Result.push_back(std::make_pair(cast<ConstantInt>(ResC), *PI));
       }
       
       return !Result.empty();
@@ -498,7 +499,8 @@ bool JumpThreading::ProcessBlock(BasicBlock *BB) {
   //     br COND, BBX, BBY
   //  BBX:
   //     br COND, BBZ, BBW
-  if (!Condition->hasOneUse() && // Multiple uses.
+  if (!LVI &&
+      !Condition->hasOneUse() && // Multiple uses.
       (CondInst == 0 || CondInst->getParent() != BB)) { // Non-local definition.
     pred_iterator PI = pred_begin(BB), E = pred_end(BB);
     if (isa<BranchInst>(BB->getTerminator())) {
@@ -532,8 +534,9 @@ bool JumpThreading::ProcessBlock(BasicBlock *BB) {
       return ProcessJumpOnPHI(PN);
   
   if (CmpInst *CondCmp = dyn_cast<CmpInst>(CondInst)) {
-    if (!isa<PHINode>(CondCmp->getOperand(0)) ||
-        cast<PHINode>(CondCmp->getOperand(0))->getParent() != BB) {
+    if (!LVI &&
+        (!isa<PHINode>(CondCmp->getOperand(0)) ||
+         cast<PHINode>(CondCmp->getOperand(0))->getParent() != BB)) {
       // If we have a comparison, loop over the predecessors to see if there is
       // a condition with a lexically identical value.
       pred_iterator PI = pred_begin(BB), E = pred_end(BB);